Vertical-scale spatial influence of radial oxygen loss on rhizosphere microbial community in constructed wetland. (January 2023)

• Record Type: Journal Article
• Authors: Bai, Shunwen; Chen, Juntong; Guo, Mengran; Ren, Nanqi; Zhao, Xinyue
• Is Part Of: Environment international. Volume 171(2023)
• Publication Date: 2023-01
• Subjects: Constructed wetland microcosm -- Radial oxygen loss -- Microbial communities -- Pollutants removal; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2022.107690
• Languages: English
• ISSNs: 0160-4120

Abstract

Graphical abstract: Highlights: ROL decreased along the vertical spatial scale of the rhizosphere in CWs. ROL was positively correlated with nitrogen removal in CWs. ROL modified rhizosphere environment and provided suitable niches for bacteria. ROL enriched nitrifying and denitrifying genes in vertical spatial layers. Abstract: Complex interactions between plants and microorganisms form the basis of constructed wetlands (CWs) for pollutant removal. In the rhizosphere, radial oxygen loss (ROL) plays a key role in the activity and abundance of functional microorganisms. However, little has been done to explore how ROL would influence the niche differentiation of microbial communities at different vertical spatial scales. We demonstrate that ROL decreases with depth, promoting an oxidation-reduction rhizosphere microecosystem in CWs. The high level of ROL in the upper layer could support the oxygen supply for aerobic bacteria ( Haliangium ), facilitating the COD (60%) and NH4 + -N (50%) removal, whereas the enrichment of denitrifiers (e.g., Hydrogenophaga and Ralstonia ) and methanotrophs (Methanobaterium ) in the lower layer could stimulate denitrification. The function prediction results further certified that the abundance of genes catalyzing nitrifying and denitrification processes were significantly enhanced in the upper and bottom layers, respectively, which was attributed to the oxygen concentration gradient in the rhizosphere. This study contributes to further unraveling the rhizosphere effect and enables an improved understanding of the decontamination mechanisms of CWs.